This invention relates generally to fluid motors, more particularly to rotor and stator seals for vane operated fluid actuated, oscillating reversing motor adapted to provide reciprocatory rotary motion through a portion of a revolution.
Devices of the type are capable of many uses such as closing or opening valves, toggling, camming, clamping, positioning, etc. and the like or performing other services, particularly where "push-pull" or reciprocatory movements are involved. Such actuators usually embody a housing head, a chamber in which a vane is moved first in one direction and then the other to provide a rotary action on a cooperative shaft throughout a portion of a revolution. In such arrangements the vane is impelled to and fro by the pressure of the fluid admitted to one side or the other of the piston or vane within the chamber and with the concurrent exhaust of fluid at the opposite side. Stators can be provided in some such devices to define additional chambers.
Previous arrangements in such rotary type actuators have required frequent servicing and replacement of the seals due to wear, particularly under heavy duty service to assure satisfactory operation of the device with a minimum amount of fluid leakage. Prior art arrangements generally provide seals for pneumatic system where the leakage rate is in the order of 0.1 cubic feet per minute and in some instances the leak rate is considerably higher.
Various prior art arrangements are available, but in such arrangements in pneumatic systems, the pressure required for initial movement of the shaft is excessive due to friction caused by the prior art sealing arrangements.
One prior art arrangement is shown in U.S. Pat. No. 3,128,679,--Trendle wherein a rotary device is shown having a chamber with a vane and a seal arrangement including an internal seal formed around the inner end of a shaft bore where the shaft passes through the head of the device. Trendle utilizes a seal member of generally square cross section.
Somewhat similar devices are shown in U.S. Pat. No. 2,806,451--Vinkler and U.S. Pat. No. 3,682,050--Hyde. In both arrangements, two piece vane seals are shown.
Other arrangements for vane type actuators are shown in U.S. Pat. No. 3,131,610--Paulus, wherein a seal arrangement is provided around the entire periphery of the vane and in U.S. Pat. No 3,179,020 where a split vane is provided with a seal captured between the sections of the vane.
Our Co-pending application Ser. No. 235,533 filed Feb. 18, 1981 shows a seal arrangement which is generally satisfactory but the present invention provides a seal having features not taught in the aforenoted application.
No prior seal is known for use in an actuator device which does not require stiffening or backup support when applied to a vane or stator member in a rotary actuator device to prevent rolling or twisting of the seal under dynamic conditions.